Apparatus for shooting studs into solid material



Oct. 16, 1962 APPARATUS FOR SHOOTING STUDS INTO SOLID MATERIAL Filed Aug. 15, 195s 2 Sheets-Sheet l Oct. 16, 1962 M. HILTI 3,058,116

APPARATUS FOR SHOOTING STUDS INTO SOLID MATERIAL Filed Aug. 15, 1958 2 Sheets-Sheet 2 Fig. 4

INVENTOR ,go-afin Z MWMJW ATTOR YS 3,058,116 APPARATUS FOR SHGO'IING STUDS INTO SOLD) MATERIAL Martin Hilti, Vaduz, Liechtenstein, assigner to Anstalt fr Montage-Technik, Vaduz, Liechtenstein Filed Aug. 15, 1958, Ser. No. 755,157 Claims priority, application Germany Aug. 16, 1957 2 Claims. (Ci. 1-445) This invention relates to shooting devices, e.g. of the powder-actuated type, for driving studs and the like into solid material such as brick Walls, concrete and iron. More particularly, this invention relates to such devices wherein the stud is driven by a guided plunger which in turn is driven by the combustion gases of a cartridge.

A wide variety of devices of this general type have, of course, been known in the prior art. These prior devices, however, have had a number of important disadlvantages. For example, it has previously been proposed to support the cartridge in a stationary holder with the cartridge base facing rearward, i.e. away from the driving direction. In such an arrangement, the gases from the cartridge act on the plunger in the manner of an engine piston. However, in devices of this construction, the guiding surfaces within the tool quickly become dirty since the combustion gases travel around the head of the plunger and contaminate the plunger and the stud guides With unburned powder particles, thus making them sticky. These unburned particles of the propellant charge adhere -rmly to the guide surfaces and even after a short time prevent use of the tool.

Accordingly, it is an object of the present invention to provide a stud-driving device that is superior to those provided heretofore. It is a particular object of this invention to provide a powder-actuated stud-driving device which is arranged to operate with reduced contamination of the guides or the plunger by the combustion residues :of the propellant charge.

In an embodiment of the present invention to be described hereinbelow in more detail, the cartridge is held in a movable support with the cartridge base facing towards the front, i.e. in the driving direction. With this arrangement, the pressure exerted by the combustion of the propellant charge exerts a force on the cartridge base so as to drive the plunger and the stud in a forwardly direction. The combustion gases Yof the propellant charge do not enter the barrel of the tool or come in contact with the various guiding surfaces. Instead, these gases enter an expansion chamber provided in the cartridge holder, to the rear of the cartridge, and pass from there into the atmosphere through the handle, which acts as a sound absorber. Moreover, in this arrangement the movable cartridge holder applies force to the plunger until complete combustion of the propellant charge has been etfected.

Other objects, advantages and aspects of the present invention will be in part apparent from, and in part pointed yout in, the following description of a preferred embodiment of the invention, considered together with the accompanying drawings in which:

FIGURE 1 is a longitudinal central section through the tool;

- FIGURE 2 shows a modification of the stud-support- 3,58%,llti Patented ct. 16, 1962 ing portions of the tool, also in longitudinal central section;

FIGURE 3 shows a further modification of the studsupporting portions of the tool, also in longitudinal central section;

FIGURE 4 is a longitudinal section of the tool shown in FIGURE l, but with the tiring mechanism in fullyactuated position prior to iiring of the cartridge;

FIGURE 5 is a cross-section taken along line 5-5 of FIGURE 4, showing details of the bayonet coupling; and

FIGURE 6 is a cross-section taken along line 6-6 of FIGURE 4 showing details of the friction spring.

Referring now to FIGURE 1, the tool includes a plunger 2 at the upper end of which is a plunger head 3 carrying a friction spring 4 positioned inV an annular groove of the head, the plunger being supported in a barrel 1. Opposite the rear end of the plunger head 3, and at a short distance therefrom to accommodate a tiring pin 39a fastened to the plunger head, is the base 6 ot a cartridge 5 which is supported in a movable cartridge holder 7. The cartridge holder 7 is slidably mounted in the base part S and is movable through the slide region 9 formed by an annular shoulder 10 and a stop 11. The cartridge holder 7 also is provided with openings 12 through which the combustion gases may escape. The upper end of the cartridge holder 7 rests against a locking sleeve 13 which is held in the base part 8 by means of a spring ring 14.

Extending out from the rear of the tool is a regulator screw 15 which is turnably supported by threads 16 in the locking sleeve 13. Against the front end 17 of this screw, there is pressed the shoulder 18 of a regulator pin 19, the diameter of which behind the cartridge is greater than the caliber of the cartridge. This pin is provided with sealing grooves 20. The base part 8 is tirmly connected with the handle 21, Between the base part and the handle there is a ring-shaped hammer 22 with a firing spring 23. The hammer 22 is formed with a groove 24 which engages a cocking pawl 25. The cocking pawl is supported in such a manner that it can be rotated clockwise about the pivot 26 carried by lever 27, but is prevented from rotating counterclockwise about this pivot by the engagement of stop 28 with an abutment on lever 27. A spring 29 normally holds the stop 28 of the cooking pawl 25 against the lever abutment. The lever 27 is supported by a pivot pin 30 in the handle 21, while the pivot pin 26 in lever 27 extends int-o a slot in a cocking lever 31 to provide driving engagement therebetween. The cocking lever 31 is swingable about a pin 32 which is seated in the handle 21. Between the handle and the cooking lever 31 there is provided a return spring 33 for the cocking lever. The handle also is formed with a gas expansion chamber 34 which communicates with the bore hole 35 of the base part 8.

The base part 3` and the barrel 1 can be disconnected from each other for loading and unloading by means of a bayonet closure 36. The barrel 1 is turnable in a bearing 37 by an amount which is limited by a projection 38, and is articulated to the handle 21. In the barrel 1, there is a stop 39 which, when the tool is pressed against the material into which the stud is to` be driven, provides 3 a limit to the movement of the firing pin 39a towards the cartridge base 6.

Removably secured to the front end of the barrel 1 is a stud-supporting device generally of the construction used for hand tools, i.e. of the type wherein a precisely centered and axially guided -stud is driven by hammer blows on a slidably mounted plunger. The outer tube 41 of this device is axially displaceable on the barrel 1 by means of the projection 42 riding within a slot 43. The inner tube 44 of this device forms a guiding surface for an insert 45 `the curved rear surface 46 of which is in contact with the plunger Z. In order to receive and guide certain types of studs, the insert 45 has centering surfaces 47 on the side and at the end. A friction ring 48 normally prevents the insert from moving to assure that the stud 49 rests in the insert. To guide the point of the stud, a centrally perforated disc Sil is provided. A friction spring 49a extends circumferentially around the outer tube 41 and at one point is formed downwardly through an opening in the outer tube so as to frictionally engage the barrel 1. Thus, this spring holds the outer tube 41 in position on the end of the barrel 1.

Referring now to FIGURE 2 which shows a mo-died form of stud-supporting device affixed to the barrel end, it can be seen that a nail 52 can be driven in by the plunger 2a without the use of an insert. The nail head 51 together with a correspondingly shaped recess on the front end of the plunger 2a forms a rear guide to center the nail 52 While the front guide is a perforated disc 53.

In FIGURE 3 there is shown a relatively long studsupporting device fastened to the end of the barrel, in order to accommodate a very long stud 54 which is centered by the insert 55 and the perforated disc 56 without having to replace the plunger 2b.

Reverting to FIGURE l, the tool is operated by forcing the cooking lever 31 back. The hammer 22 is accordingly moved backward and cocks the firing spring 23 until the tip of the cooking pawl 25 disengages so that the hammer rapidly moves forward. When the hammer strikes, the necessary detonation energy is transferred to the base part 8 which is free to move towards the barrel. The yforce o-f impact is transferred to the cartridge 5 by the cartridge holder '7, so that the base 6 of the cartridge 5 is jammed against the firing pin 39a which extends slightly beyond the rear end surface of the plunger head 3. As soon as the detonation has been effected, the cartridge base 6 is pressed by the combus-tion gas pressure against the plunger head 3. At the same time, the combustion gases expand behind the cartridge to the large diameter of the end surface of the regulating pin 19. The gas pressure, active on the cross-section of the regulating pin, also presses the cartridge holder against the plunger head 3 so that the drive of the plunger is effected from the impact base of the cartridge and by the `differential pressure between the cross-section of the regulating pin 19 and the cross-section of the cartridge caliber. After the cartridge holder 7 has followed the plunger head 3 through the slide region 9, and the gas pressure has dropped considerably, the cartridge alone follows behind the plunger head. As a result, the extraction of the cartridge is effected by the residual gas pressure. While the extraction of the cartridge is initiated by the striking of the cartridge holder against the shoulder 10, the openings 12 of the cartridge holder are at the same time exposed `so that the residual gases can blow ont via the bore 35 into the gas chamber 34 of the handle. The impact impar-ted to the cartridge by the residual gases pushes the cartridge case completely out. After the loosening of the bayonet connection between the barrel 1 and the base part 8, the handle may be swung downward to permit the empty cartridge case to drop out.

By `adjustment of the regulating pin 19, the volume of the combustion space, i.e. the charge density, may be varied. The smaller the charge density, the smaller the maximum gas pressure and therefore also the smaller the energy supplied to the stud. The regulation of the power made possible thereby permits the use of a stand- -ard charge for small and large driving energies, which constitutes a considerable simplification since only one type of cartridge is required for an infinitely variable driving action.

The operation of that part of the apparatus which guides and centers the stud is as follows:

Referring first to FIGURE 1, after a stud-driving operation the insert 45 is in the front opening in a base ange 5'8 which extends out to a wide diameter and is flattened on one side 57. The stud 49 is placed in the insert 45, the base ange 58 is pressed against the wall, and at the same time the rear part of the apparatus is pushed forward with the right hand until the stud 49 and the plunger 2 form a unit. The tool then is fired.

The same applies t0 the embodiments shown in FIG- URES 2 and 3. All the figures also show that one important advantage of the apparatus in accordance with the present invention is that hand-operated stud-driving devices can be used in conjunction with the new powderactuated tool in order lto securely hold, center and axially guide studs of different type and length. This results in considerable simplifications in manufacture. Furthermore, there is obtained an accuracy of centering and axially guiding of the stud during the driving that has not previously been known in powder-actuated stud-driving tools. These advantages particularly are obtained when the device has a base ange 58 to prevent tilting, and two guides which are positioned as far as possible away from each other in the axial direction at the commencement of the driving operation so that the shank of the stud (49, 52, 54) freely extends between the guides during the driving operation, the front guide being provided in or adjacent the base flange while the rear guide is formed in such `a manner that the head of the stud (47, 51) is guided by centering surfaces either of the tool itself or of the plunger (2, 2a) which is guided in the tool. The front guiding is effected in the example shown in FIGURES 1 through 3 by a perforated disc while the `rear end of the stud is centered in a formlocked manner in FIGURES 1 and 3 by a blunt or conical shoulder, or in FIGURE 2. by a spherical extension on the front end of the plunger.

When using perforated discs as front guides for the studs, the new apparatus provides the advantage that these perforated discs actually act as guides and are not destroyed by the combustion `gases as in prior powder- `actuated stud-driving tools.

I claim:

1. Apparatus for driving studs and the like into solid materials, comprising tubular guide means, plunger means slidably mounted within said guide means `for axial movement therein, means `at the Iforward end of said plunger means to apply -a driving force to a stud, a cartridge holder slidably mounted for axial movement adjacent the rearward end of said plunger means, said cartridge holder being formed at its `front end to receive a cartridge with its primer base facing said plunger means, firing means on the rear end of said plunger means adapted to be struck by the cartridge base to cause detonation of the cartridge, said guide means having a cross-sectional dimension greater than that of said cartridge holder and forming a clear passage for forward movement of said cartridge holder along with said plunger means after `detonation of the cartridge has been effected.

2. Apparatus for driving studs and the like into solid materials, comprising tubular guide means, first plunger means slidably mounted for axial movement within said guide means, means at the forward end of said first plunger means to apply a driving force to a stud, second plunger means slidably mounted for axial movement adjacent the rearward end of said first plunger means, one of said plunger means being formed to receive a cartridge with its base facing the adjacent end of said other plunger means, firing means at said adjacent end of said other plunger means, said firing means and said cartridge base References Cited in the file of this patent UNITED STATES PATENTS Temple Feb. 11, 1936 Tietig Mar, 31, 1953 Trautmann Nov. 17, 1953 Termet Nov. 22, 1955 Williams Sept. 4, 1956 Maier Mar, 17, 1959 Kopf et a1. July 19, 1960 FOREIGN PATENTS Norway Aug. 23, 1954 Sweden Apr. 26, 1955 Belgium Sept. 30, 1957 Germany Jan. 10, 1957 

